RMAN : Deleting Backups

Deleting the backups :

RMAN> delete noprompt backup; --------> delete backups without any prompts
using channel ORA_DISK_1
List of Backup Pieces
BP Key  BS Key  Pc# Cp# Status      Device Type Piece Name
------- ------- --- --- ----------- ----------- ----------
4       4       1   1   AVAILABLE   DISK        /u01/app/oraclebase/fast_recovery_area/TESTDB2/backupset/2017_12_20/o1_mf_nnndf_TAG20171220T135301_f3n7h5k2_.bkp
5       5       1   1   AVAILABLE   DISK        /u01/app/oraclebase/fast_recovery_area/TESTDB2/backupset/2017_12_20/o1_mf_ncsnf_TAG20171220T135301_f3n7k9sv_.bkp
6       6       1   1   AVAILABLE   DISK        /u01/app/oraclebase/fast_recovery_area/TESTDB2/backupset/2017_12_20/o1_mf_annnn_TAG20171220T135411_f3n7kcp0_.bkp
deleted backup piece
backup piece handle=/u01/app/oraclebase/fast_recovery_area/TESTDB2/backupset/2017_12_20/o1_mf_nnndf_TAG20171220T135301_f3n7h5k2_.bkp RECID=4 STAMP=963237181
deleted backup piece
backup piece handle=/u01/app/oraclebase/fast_recovery_area/TESTDB2/backupset/2017_12_20/o1_mf_ncsnf_TAG20171220T135301_f3n7k9sv_.bkp RECID=5 STAMP=963237249
deleted backup piece
backup piece handle=/u01/app/oraclebase/fast_recovery_area/TESTDB2/backupset/2017_12_20/o1_mf_annnn_TAG20171220T135411_f3n7kcp0_.bkp RECID=6 STAMP=963237251
Deleted 3 objects

RMAN> list backup;

specification does not match any backup in the repository